I can't say how 3 M2's across the front would sound, but I can say I am very pleased with my M3's in a similar setup. Without a sub they performed well, but adding the AV123 X-Sub took it to another level. If you add a decent sub to the M2's I would imagine that you would be quite happy.

M3's(LCR), Onix X-Sub, Marantz SR5200